BlueTooth Low Energy (aka BLE) is a low energy variant of the BlueTooth short range wireless standard that was introduced as part of the BlueTooth 4.0 specification. Further details about BLE and the Bluetooth 4.0 specification may be found at https://www.bluetooth.org/en-us/specification/adopted-specifications and https://developer.bluetooth.org/TechnologyOverview/Pages/BLE.aspx which are incorporated herein by reference. The purpose of BLE is to provide an extremely low power wireless system similar in power consumption to Zigbee. Zigbee is an older wireless low power communication standard.
Shortly after the introduction of BLE chipsets, Apple® introduced a product called iBeacon along with a simple protocol specification, all based on BLE. Further details of the iBeacon product and its protocol specification may be found at https://developer.apple.com/ibeacon/ which is incorporated herein by reference. iBeacon provides a BLE beacon (transmit only) that devices (e.g. cell phones) may receive and use to determine a rough location. The location technology is simple proximity based on the RSSI (received signal strength indication) of the beacon as seen by the receiving device.
In addition, a differential location service, based on BLE broadcast messages, exists in which a location algorithm is used in conjunction with RSSI and other information to determine an RTLS (real time location system)-level accurate location. In these known systems, the service operates with only a single beacon and the beacon uses a omnidirectional antenna. However, these known system do not provide rapid room entry.